• Open today's
Logger
Pro and
spreadsheet
files. Place the 500-g mass on top of the hanger. Use the
mass balance to determine the mass of the hanger plus the 500-g mass,
and enter it into the appropriate yellow cell in the spreadsheet.
• Hang the spring from the equipment stand and stabilize the
combined mass hanger and 500-g mass in its equilibrium position.
Adjust the height of the bar of the equipment stand such that the
bottom of the hanger is about 30 cm above the table.
• Remove the 500-g mass. Center the
active element of the motion sensor below the hanger. Click on
the Zero
button in the top
toolbar, just to the left of the green Collect button. This tells
the
motion sensor that you want the zero of position to correspond to the
bottom of the hanger where the spring is unstretched, as it nearly is
when it supports only the hanger.
• Gently replace the 500-g mass on the hanger such that the
mass does not drop onto the motion sensor.
Slowly return the hanger to its equilibrium
position. Then pull it down from equilibrium by just a few
centimeters
and smoothly release it such that it moves only in the vertical
direction.
Collect data. You will see a sine
wave. Click on the Curve-Fit button at the top of your
screen. In the pop-up window, scroll down the list of functions
until you read “A sin(Bt+C) + D” and choose it. Click on “Try
Fit,” then “OK.” A solid black line will appear on the screen,
along with the fitted values for A, B, C, and D. The value B is
the radial frequency, which you should enter into the appropriate
yellow cell in the spreadsheet.
• Undo the curve fit. Zoom in on one clean (i.e. no
noise)
period by highlighting the interesting region, right-clicking the
screen, and choosing “Zoom In” on the top toolbar (magnifying glass
with “+” sign). Use the Linear-Fit (“R=”) function to find the
slope at nine sets of three adjacent points, roughly equally spaced, of
one
period. Use the Examine (“X=”) function to determine the position
and time for each central point of your linear fits. Record the
time, position,
and velocity for each of your nine central points in the yellow cells
of the
spreadsheet. Copy and paste the fully annotated Logger-Pro plot that
includes the nine different linear-fit data boxes into the answer box
for Question 4 of your worksheet. You might need to decrease the
size of the plot, such that the data boxes consume a larger portion of
it.
• Enter the time of your first datum point of your sequence of
data into the yellow time-offset cell of the
spreadsheet in order to start the time axis at zero. If your
fractional uncertainty (the standard deviation divided by the
average, the bottom value of the green cells) is not less than 0.100,
you should ask a lab instructor what
might be wrong.
• Copy and
paste the data within the bold outline of the spreadsheet into the area
below Question 5 of your worksheet. Copy and
paste the E(t) graph from the spreadsheet into the answer box for
Question 6. Read the information in the green
cells of the spreadsheet in order to individually report your result
for E(t) in
standard
form for Question 7.
Finally, individually answer the
other
parts of Question 7.